Hydroformylation catalyst and process of using it

ABSTRACT

A novel catalyst and the process of using it for hydroformylation where the catalyst is a complex of the formula Pt(Acetylacetonate) 2  /nMX 2 .nH 2  O/xPR 3  where M is a Group IVA metal, X is a halogem atom, n is an integer of from about 2 to about 10, x is an integer of from about 5 to about 20, n is 0 or 2, and PR 3  is a phosphine where R is an alkyl or, aryl group.

BACKGROUND OF THE INVENTION

The use of platinum II complexes as a catalyst for hydroformylation (OXO reaction) is known. Thus, for example, PtH(SnCl₃)(PPh₃)₂ are shown by Hsu and Orchin, J. Amer. Chem Soc., 97 353 (1975) to be useful for conversion of 1-pentene to aldehydes. Schwager and Knifton, J. Cat. 45, 256 (1976), U.S. Pat. No. 3,981,925 and U.S. Pat. No. 3,996,293 disclose use of PtCl₂ (PPh₃)₂ +SnCl₂ for a similar reaction with 1-heptene. Kawabata, et al., J.C.S. Chem. Comm 462 (1979) teach Pt(PhCN)₂ Cl₂ +Ph₂ P(CH₂)_(x) PPh₂ for conversion of 1-pentene to aldehydes. U.S. Pat. Nos. 4,101,565 and 4,155,939 show the dimer (PtCl₂ PPh₃)₂ +SnCl₂ for hydroformylation of 1-hexene. U.S. Pat. No. 3,876,672 also shows hydroformylation of 1-hexene with PtH(PPh₃)₃ ⁺ HSO₄ ⁻.

In the hydroformylation reaction of olefin with such catalysts the reaction proceeds as follows: ##STR1##

In such reactions, usually greater than 90% selectivity (relative to total aldehydes) to linear aldehydes is obtained when a platinum complex is employed as a catalyst. However, when propylene is the olefin, lower yield and selectivity to linear aldehyde (n-butyraldehyde) is obtained and this is shown by the work of Knifton and his associates referred to above. It is to be understood that with a chemical commodity such as n-butyraldehyde, even a small increase in selectivity to the desired linear product is highly desirable because of the large volumes processed. This invention provides a novel catalyst which gives improved selectivity and yield to linear aldehydes particularly for n-butyraldehyde and thus makes a significant advance in the art.

STATEMENT OF INVENTION

This invention provides a novel hydroformylation catalyst which is a complex characterized by the formula Pt(Acetylacetonate)₂ /MX₂ nH₂ O/PR₃ where M is a Group IVA metal, X is halogen atom n is 0 or 2, and PR₃ is a phosphine where R is an alkyl, aryl or mixed alkyl-aryl group. The invention also embodies the hydroformylation process with the novel catalyst.

DISCUSSION OF INVENTION

The hydroformylation reaction is also known as the OXO process and is well known in the art (see for example Kirk-Othmer Encyclopedia of Chemical Technology). The catalyst of the invention may be employed under the usual conditions for such reactions, but preferred reaction conditions will be from about 20° to about 150° C. (preferably from about 75° to about 110°) at elevated pressure of from about 250 to about 3000 psig. The amount of catalyst may vary over a wide range; e.g., from about 0.01 to about at 5% of olefins used (preferably from about 0.1 to about 1% with about 0.4% being most preferred).

The novel catalyst is employed in a homogeneous system and the solvents used will be selected from a wide variety of known solvents for the OXO reaction such as aromatic hydrocarbons, aldehydes, ketones, acetophenone, and the like. The catalyst is easily made simply by mixing together in the solvent the catalyst components of platinum acetylacetonate (PtAcAc)₂, a metal salt of formula MX₂ where M is a Group IVA metal such as tin (preferred), germanium or lead, and X is a halogen atom (chlorine preferred), which salt may be anhydrous (n=0) or the dihydrate (n=2), and a phosphine of formula PR₃ where R is an alkyl or aryl group and in which the three R groups of the phosphine may be the same or different. The R groups of the phosphine will generally contain from one to six carbon atoms when alkyl or from six to twelve carbon atoms when aryl. Typical R groups are methyl, ethyl, hexyl, phenyl (preferred), naphthyl, tolyl, xylyl, and the like. The ratio of platinum to Group IVA metal to phosphine will vary over a wide range, but will generally be from about 2 to about 10 moles (about 5 preferred) of Group IVA metal per mole of platinum and from about 5 to about 20 (about 2.5 to about 5.0 preferred) of phosphine per mole of platinum. Thus, the catalyst may be formulated as Pt(AcAc)₂ /mMX₂ nH₂ O/xPR₃ where n is from about 2 to about 10 and x is from about 5 to about 20, n, and R being identified above.

The process of the invention is operable with the wide variety of olefins susceptible to hydroformylation and will include, preferably, the C₂ to C₂₀ aliphatic and cycloaliphatic olefins.

In order to illustrate the advantages of the novel catalyst, the following examples are given.

EXAMPLE 1 (Prior Art)

This example illustrates the hydroformylation of propylene to butyraldehyde in the presence of a prior art platinum catalyst in a manner similar to that disclosed in U.S. Pat. No. 3,981,925.

To a 300 ml stainless steel autoclave was added 100 ml of toluene as solvent, 0.53 g (1.0 mmole) of PtCl₂ (PPh₃)₂, 1.14 g (5.0 mmole) of SnCl₂.2H₂ O, and 1.31 g (5.0 mmole) of PPh₃. After the mixture was stirred for 15 minutes under a nitrogen atmosphere, the autoclave was purged with syngas (H₂ /CO=1:1) and 10.5 g (250 mmole) of propylene was added. The autoclave was then charged with syngas (H₂ /CO=1:1) to make a total pressure of 750 psig. After which the reactor was then quickly heated to 100° C. and the syngas pressure was maintained at 1000 psig through constant addition of syngas from a reservoir. After 4 hours of reaction, the autoclave was cooled to room temperature and the gas phase materials were vented. The liquid contents were removed and analyzed directly by vapor phase chromatography. Analysis of the reaction mixture indicated that 85 % yield of butyraldehydes was obtained and the molar ratio of n-butyraldehyde to iso-butyraldehyde was 6.7 (i.e., 87% of normal aldehyde).

EXAMPLE 2 (The Invention)

This example illustrates the hydroformylation of propylene to butyraldehyde in the presence of a catalyst of the present invention.

In a manner similar to that described in Example 1, an autoclave was charged with 100 ml of toluene, 0.39 g (1.0 mmole) of Pt(AcAc)₂, 1.14 g (5.0 mmole) of SnCl₂.2H₂ O, and 1.31 g (5.0 mmole) of PPh₃. After the mixture was stirred for 15 minutes under nitrogen atmosphere, the autoclave was purged with syngas (H₂ /CO=1:1) and 10.5 g (250 mmole) of propylene was added. The autoclave was then charged with 750 psig of syngas (H₂ /CO=1:1) and quickly heated to 100° C., whereupon the total pressure was adjusted to 1000 psig by the use of a syngas reservoir. After 5 hours of reaction, the autoclave was cooled, and the liquid mixture was analyzed using vapor phase chromatography. Analytical data indicated the yield of butyraldehyde was 95% and the ratio of n-butyraldehyde to iso-butyraldehyde was 21 to 1, corresponding to 96% of normal butyraldehyde.

EXAMPLES 3-5

In these examples, summarized in Table I, the reaction procedure is similar to that shown in Example 2. The main difference is in the variation of reaction temperature as illustrated in these examples. Higher normal to iso-butyraldehyde ratio was obtained when the reaction temperature was lowered.

EXAMPLES 6-11

In these examples, summarized in Table II, the reaction procedures are similar to that shown in Example 2, the major differences are the variation in syngas total pressure and the ratio of H₂ to CO in syngas composition.

EXAMPLES 12-17

In these examples, summarized in Table III, the reaction procedures are similar to that shown in Example 2, the major differences are the use of various types of solvents.

EXAMPLES 18-22

Variation in catalyst composition are illustrated in these examples. The reaction procedures used for these examples are similar to that described in Example 2. The reaction conditions and results are summarized in Table IV.

                  TABLE I                                                          ______________________________________                                                      Example 3                                                                              Example 4 Example 5                                       ______________________________________                                         Reagents                                                                       Propylene      245 mmole 238 mmole 240 mmole                                   Pt(AcAc).sub.2 1.0 mmole 1.0 mmole 1.0 mmole                                   SnCl.sub.2.2H.sub.2 O                                                                         5.0 mmole 5.0 mmole 5.0 mmole                                   PPh.sub.3      5.0 mmole 5.0 mmole 5.0 mmole                                   Toluene        100 ml    100 ml    100 ml                                      H.sub.2 /CO (1:1)                                                                             1000 psig 1000 psig 1000 psig                                   Conditions                                                                     Temperature    80° C.                                                                            90° C.                                                                            100° C.                              Reaction Time  6 hr.     6 hr.     6 hr.                                       Results                                                                        Yield of C.sub.4 - Aldehydes                                                                  83%       91%       95%                                         Ratio of n/iso-                                                                               98/2      97/3      95/5                                        butyraldehyde                                                                  ______________________________________                                    

                                      TABLE II                                     __________________________________________________________________________                   Example 6                                                                             Example 7                                                                             Example 8                                                                             Example 9                                                                            Example 10                                                                           Example 11                      __________________________________________________________________________     Reagents                                                                       Propylene     254 mmole                                                                             258 mmole                                                                             251 mmole                                                                             245 mmole                                                                            250 mmole                                                                            253 mmole                       Pt(Acac).sub.2                                                                               1.0 mmole                                                                             1.0 mmole                                                                             1.0 mmole                                                                             1.0 mmole                                                                            1.0 mmole                                                                            1.0 mmole                       SnCl.sub.2.2H.sub.2 O                                                                        5.0 mmole                                                                             5.0 mmole                                                                             5.0 mmole                                                                             5.0 mmole                                                                            5.0 mmole                                                                            5.0 mmole                       PPh.sub.3     5.0 mmole                                                                             5.0 mmole                                                                             5.0 mmole                                                                             5.0 mmole                                                                            5.0 mmole                                                                            5.0 mmole                       Solvent       Ethylbenzene                                                                          Ethylbenzene                                                                          Ethylbenzene                                                                          Toluene                                                                              Toluene                                                                              Toluene                                       (100 ml)                                                                              (100 ml)                                                                              (100 ml)                                                                              (100 ml)                                                                             (100 ml)                                                                             (100 ml)                        H.sub.2 /CO (1:1)                                                                            1000 psig                                                                             --     --     700 psig                                                                             1500 psig                                                                            1250 psig                           (2:1)     --     1000 psig                                                                             --     --    --    --                                  (3:1)     --     --     1000 psig                                                                             --    --    --                              Conditions                                                                     Temperature   95° C.                                                                         95° C.                                                                         95° C.                                                                         100° C.                                                                       100° C.                                                                       100° C.                  Reaction Time 4.0 hr*                                                                               5.0 hr 5.0 hr 5.0 hr                                                                               5.0 hr                                                                               5.0 hr                          Results                                                                        Yield of C.sub.4 - Aldehydes                                                                 78%    94%    83%    85%   94%   97%                             Ratio of n/iso-butyraldehyde                                                                 96/4   97/3   95/5   95/5  97/3  95/5                            __________________________________________________________________________      *Reaction incomplete in this time                                        

                                      TABLE III                                    __________________________________________________________________________                   Example 12                                                                             Example 13                                                                             Example 14                                                                             Example 15                                                                           Example 16                                                                           Example                      __________________________________________________________________________                                                       17                           Reagents                                                                       Propylene     250 mmole                                                                              251 mmole                                                                              246 mmole                                                                              249 mmole                                                                            251 mmole                                                                            254 mmole                    Solvent       Acetophenone                                                                           Acetophenone                                                                           Acetophenone                                                                           Xylenes                                                                              Tetralin                                                                             MIBK                         (100 ml)                                                                       Pt(AcAc)      1.0 mmole                                                                              1.0 mmole                                                                              1.0 mmole                                                                              1.0 mmole                                                                            1.0 mmole                                                                            1.0 mmole                    SnCl.sub.2.2H.sub.2 O                                                                        5.0 mmole                                                                              5.0 mmole                                                                              5.0 mmole                                                                              5.0 mmole                                                                            5.0 mmole                                                                            5.0 mmole                    PPh.sub.3     5.0 mmole                                                                              5.0 mmole                                                                              5.0 mmole                                                                              5.0 mmole                                                                            5.0 mmole                                                                            5.0 mmole                    H.sub.2 /CO (1:1)                                                                            1000 psig                                                                              1000 psig                                                                              1500 psig                                                                              1000 psig                                                                            1000 psig                                                                            1000 psig                    Conditions                                                                     Temperature   90° C.                                                                          100° C.                                                                         100° C.                                                                         100° C.                                                                       100° C.                                                                       100° C.               Reaction Time 5.5 hr  6.0 hr  5.0 hr  4.0 hr                                                                               4.0 hr                                                                               4.0 hr                       Results                                                                        Yield of C.sub.4 - Aldehydes                                                                 62%     67%     86%     94%   77%   60%                          Ratio of n/iso-butyraldehyde                                                                 97/3    95/5    96/4    97/3  96/4  96/4                         __________________________________________________________________________      MIBK = Methyl Isobutyl Ketone                                            

                                      TABLE IV                                     __________________________________________________________________________                   Example 18                                                                           Example 19                                                                           Example 20                                                                           Example 21                                                                            Example 22                              __________________________________________________________________________     Reagents                                                                       Propylene     250 mmole                                                                            256 mmole                                                                            248 mmole                                                                            250 mmole                                                                             250 mmole                               Pt(AcAc).sub.2                                                                               1.0 mmole                                                                            1.0 mmole                                                                            0.5 mmole                                                                            1.0 mmole                                                                             1.0 mmole                               SnCl.sub.2.2H.sub.2 O                                                                        2.5 mmole                                                                            2.5 mmole                                                                            2.5 mmole                                                                            None   5.0 mmole                               PPh.sub.3     5.0 mmole                                                                            2.5 mmole                                                                            2.5 mmole                                                                            5.0 mmole                                                                             None                                    Ethylbenzene Solvent                                                                         100 ml                                                                               100 ml                                                                               100 ml                                                                               100 ml 100 ml                                  H.sub.2 /CO (1:1)                                                                            1000 psig                                                                            1000 psig                                                                            1000 psig                                                                            1000 psig                                                                             1000 psig                               Conditions                                                                     Temperature   100° C.                                                                       95° C.                                                                        95° C.                                                                        100° C.                                                                        100° C.                          Time          4 hr  4 hr  5 hr  4 hr   4 hr                                    Results                                                                        Yield of C.sub.4 - Aldehydes                                                                 93%   80%   60%   No Reaction                                                                           5%                                      Ratio of n/iso-butyraldehyde                                                                 97%   95/5  96/4  No Reaction                                                                           50/50                                   __________________________________________________________________________

EXAMPLE 23

This example illustrates that in the presence of the catalyst of the invention the higher olefins such as 1-pentene can be hydroformylated to give high yield of hexanal and give a high ratio of linear to branched aldehydes.

To a 300 ml stainless steel autoclave was added 100 ml of ethylbenzene solvent, 0.39 g (1.0 mmole) of Pt(AcAc)₂, 1.14 g (5.0 mmole) of SnCl₂.2H₂ O, and 1.31 g (5.0 mmole) of PPh₃. After the mixture was purged with syngas (H₂ /CO=1:1) and 17.5 g of 1-pentene (250 mmole) was added. The autoclave was then charged with 750 psig of syngas (H₂ /CO=1:1) and quickly heated to 100° C., whereupon the total pressure was adjusted to 1000 psig by the use of a syngas reservoir. After 5 hours of reaction, the autoclave was cooled to room temperature and the excess gas was vented. The liquid reaction was removed and analyzed using vapor phase chromatography. Analytical data indicated that 95% yield of C₆ -aldehydes was obtained. The ratio of 1-hexanal to 2-hexanal was 97 to 3. 

I claim:
 1. In the process of hydroformylating an olefin containing 2 to about 20 carbon atoms by reacting the olefin with hydrogen and carbon monoxide at elevated pressure in the presence of a catalyst to produce an aldehyde, the improvement of using as catalyst a complex of the formula Pt(Acetylacetonate)₂ /mMX₂.nH₂ O/xPR₃ where M is a Group IVA metal, X is a halogen atom, m is an integer from about 2 to about 10, n is 0 or 2, x is an integer from about 5 to about 20, and PR₃ is a phosphine where R is an alkyl or aryl group.
 2. The process of claim 1 wherein M is tin.
 3. The process of claim 1 wherein MX₂ is SnCl₂.
 4. The process of claim 1 wherein the phosphine is triphenylphosphine.
 5. The process of claim 1 wherein the catalyst is Pt(Acetylacetonate)₂ /5SnCl₂.2H₂ O/5PPh₃.
 6. The process of claim 1 wherein the olefin is propylene.
 7. The process of claim 5 wherein the olefin is propylene.
 8. The process of claim 1 wherein the olefin is 1-pentene.
 9. The process of claim 1 wherein MX₂ is SnCl₂ and the phosphine is triphenylphosphine. 